Search found 854 matches

by Fischerman
Thu Mar 28, 2024 3:50 pm
Forum: Trainwreck Discussion
Topic: my 18 watt rocket-ish build
Replies: 72
Views: 13535

Re: my 18 watt rocket-ish build

I recently built a Matchless Lightning clone (which is in that same family and around 15W) and also an 18W Liverpool. The Lightning used alleged Matchless transformers (from amppartsdirect) and the OT is 3k7 ohms at 4/8/16 ohm secondary which is around what a 4xEL84 amp would be. It’s pretty bass he...
by Fischerman
Thu Mar 21, 2024 3:54 pm
Forum: Trainwreck Discussion
Topic: 2xEL84 Liverpuddle
Replies: 14
Views: 4973

Re: 2xEL84 Liverpuddle

You make me do bad things to great circuits that are naturally a little problematic. :) I often wish my Liverpool was a Rocket. Here’s my Rocket I built way back during the big RJ Rocket build. I had the cab built to match an old Carvin 1x12 I had. It has evolved into a Matchless DC30. https://i.po...
by Fischerman
Mon Mar 18, 2024 11:06 pm
Forum: Trainwreck Discussion
Topic: 2xEL84 Liverpuddle
Replies: 14
Views: 4973

Re: 2xEL84 Liverpuddle

So what impedence of an ot did you go with. And does it still clean up when you back of the volume. Thanks Bill The OT is 5k9 at 2/4/8 ohms but I’m running it at 4/8/16. Yes it cleans up but I deviated from the Liverpool enough for it to not be apple-to-apples. For me, originally it was just a brig...
by Fischerman
Sun Feb 04, 2024 7:49 pm
Forum: Trainwreck Discussion
Topic: 2xEL84 Liverpuddle
Replies: 14
Views: 4973

Re: 2xEL84 Liverpuddle

10nF was too much. That spot is really sensitive to coupling cap changes. I put in a 4n7 and turned the grid leak up to 54k. That vocal-mid-focus is gone but geez it has a ton of gain. Then it occurred to me that I never turn the Presence up to 3:00, which is where it really starts to ramp up. Most ...
by Fischerman
Sun Feb 04, 2024 11:15 am
Forum: Trainwreck Discussion
Topic: 2xEL84 Liverpuddle
Replies: 14
Views: 4973

Re: 2xEL84 Liverpuddle

This thing screams but it's a bit too focused in the midrange. I originally used 1M Treble/Bass/Volume pots but reduced the Treble to 500k. I'm going to try 47n output couplers and then play with that coupler preceding stage 3. I have that Stage 3 grid leak adjustable with a 39k resistor in series w...
by Fischerman
Mon Jan 29, 2024 5:27 pm
Forum: Trainwreck Discussion
Topic: 2xEL84 Liverpuddle
Replies: 14
Views: 4973

Re: 2xEL84 Liverpuddle

Nice! I didn't know you could get a 3-position switch that's not "off" in the centre. What kind is it? What sort of volume control are you using? VVR or a PPIMV? Did you change the 25W resister from a 1K to 1.7K for a pair of EL84s like Mark Abbot's schematic suggests? I ask because I just realized...
by Fischerman
Mon Jan 29, 2024 4:33 pm
Forum: Trainwreck Discussion
Topic: 2xEL84 Liverpuddle
Replies: 14
Views: 4973

Re: 2xEL84 Liverpuddle

Image
by Fischerman
Sat Dec 30, 2023 11:50 pm
Forum: Technical Discussion
Topic: Interesting video on current flow
Replies: 7
Views: 1472

Re: Interesting video on current flow

I stopped watching about 15 minutes in, maybe there's more interesting parts in the end of the video…
I stopped reading as soon as you wrote this. At least watch the whole thing before you shoot holes in it. It sort of invalidates your whole post.
by Fischerman
Thu Dec 14, 2023 1:14 pm
Forum: Technical Discussion
Topic: Interesting video on current flow
Replies: 7
Views: 1472

Interesting video on current flow

I thought this was interesting. I think it hints at reasons why certain grounding schemes don't work as well as others.

https://youtu.be/2AXv49dDQJw?si=Obj27QA5Ov_AhBeU
by Fischerman
Sat Dec 09, 2023 7:29 pm
Forum: Technical Discussion
Topic: Primary impedance for OTs - output and tone
Replies: 16
Views: 4792

Re: Primary impedance for OTs - output and tone

bepone wrote: Sat Dec 09, 2023 6:14 pm 3800 is not correct for 2 EL84s, it is kinda low even for one..
so speaker 8 ohm must be inserted to 4 ohm tap from the amp, then the load line will be ok (7600 ohms aa)
It sounds better that way too imo.
by Fischerman
Sat Dec 09, 2023 6:17 pm
Forum: Technical Discussion
Topic: Primary impedance for OTs - output and tone
Replies: 16
Views: 4792

Re: Primary impedance for OTs - output and tone

I wonder where the knee falls in that load line. Hopefully the plate voltage is lowish. It’s just under 350v, I don’t consider that low for EL84s. But it runs the screens differently, from an extra lower voltage node instead of straight off the other side of the choke. I've often wondered about thi...
by Fischerman
Thu Nov 16, 2023 4:33 pm
Forum: Technical Discussion
Topic: Does a 'bright cap' really boost highs?
Replies: 16
Views: 3858

Re: Does a 'bright cap' really boost highs?

Ha, thats great Max. I have from time to time imagined electron flow in strange analogous ways to give some visual to the actions. "But, to truly know the electron, you must "Be" the electron" - Bruce B+ Semi-sincerely yours, Phil D. That works better for me too sometimes. I can’t really get a grip...
by Fischerman
Sun Oct 29, 2023 11:02 am
Forum: Trainwreck Discussion
Topic: 2xEL84 Liverpuddle
Replies: 14
Views: 4973

Re: 2xEL84 Liverpuddle

Not the prettiest control panel but works for now. That’s the Lightning faceplate reversed. I hope to get a nice pro looking faceplate for this and the Lightning (with added Cut control).

I decided to add a post-PI Master Volume.

Image
by Fischerman
Fri Oct 27, 2023 5:08 pm
Forum: Marshall Discussion
Topic: New build fine tuning
Replies: 20
Views: 6881

Re: New build fine tuning

by Fischerman
Fri Oct 27, 2023 3:02 pm
Forum: Marshall Discussion
Topic: New build fine tuning
Replies: 20
Views: 6881

Re: New build fine tuning

Thanks so much! I'd love to hear some clips of that '69 build. What iron did you end up using? I think you're right about the "all access" build piece. I almost always run my amps to sound pretty similar, but you're exactly right that I wanted to hear what the different iterations of the circuit so...